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How to transfer data between apps using app designer

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Ho Nhu Y Nguyen
Ho Nhu Y Nguyen on 16 Jun 2016
Commented: TADA on 6 Aug 2020
I am working on APP1 which has a parameter x, I open APP2 by a button in APP1 and change x (which I already transfer to APP2 from APP1) in APP2.
How can I update x in APP1 when I close APP2 and come back to APP1?
I tried to put in APP2CloseRequest: APP1.x = app.x but seems it doesnt work

  1 Comment

Issa on 16 Jun 2019
how you passed x from app1 to app2?

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Answers (2)

sam0037 on 23 Jun 2016
You can use public properties as explained in the link below to share data between apps. And you can add a closeRequestFcn using the Callback button in the Editor tab of the APPDESIGNER window. Remember to add "delete(app)" in the closeRequestFcn or else the app wont close. I have attached a sample APP to illustrate the above. Run the SendData app which sends the data to RecvData app. Hope this helps.


Ho Nhu Y Nguyen
Ho Nhu Y Nguyen on 28 Jun 2016
Thanks for your response.
But what I meant is there is a button on app A, it will open app B and send data to B (I already did this) then I will change the data in app B and app A will be updated when closing app B and coming back to app A (not opening a new A).
Wouter on 5 Apr 2017
Ho Nhu Y Nguyen did you already achieved this? I stubmle upon your topic now namely and am also wondering how to implement this behavior. Can you maybe share your findings if you have any?
Ho Nhu Y Nguyen
Ho Nhu Y Nguyen on 25 Apr 2017
Hi Wouter, sorry I couldn't find the solution and currently not working on this.

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TADA on 16 Jun 2019
The simplest solution would be to couple the two apps. When you open app B send the object of app A to it. Then when app B updates x, it can update the property of app A.
A more robust solution would be to uncouple the two apps and add a mediator class. The mediator knows both app A and app B. It passes all the data between the two back and forth. Both apps don't need to know each other, only the mediator.
The reason I say this implementation is more robust is because tomorrow you may need app A to communicate with a third class instead of app B for some specific functionality. In that case you don't need to change app A, only the mediator class.


Nguyen Thuan
Nguyen Thuan on 3 Aug 2020
@TADA: Hi TADA. Could you please explain how to make a mediator class for app designer?
If you have any app example, could you please share it?
Thanks a lot in advance.
Thuan Nguyen
TADA on 6 Aug 2020
I attached a zip file with a very simple example
you have a main app which has axes and a button to open a dialogue for adding new x-y values
The dialogue has two spinners and two buttons OK and Cancel.
If you click OK the value pair from the spinners will be added to the plot
This is implemented using callbacks rather than return values from any of the methods
the AppMediator class knows how to show a new "dialogue" window, and has a callback function for when that window is done
App2 accepts the mediator in the startupFcn and then when one of the buttons is clicked it calls the callback function of the mediator and sends the spinners values.
The mediator accepts a callback function when the showDialogue function is called and it then calls this callback function when the dialogue sends an "OK" callback;
App1 also accepts the mediator in its startupFcn and in turn when its "add" button is clicked will call the mediators showValueDialogue function, it sends a function handle as a callback to the mediator
The last trick is that the mediator also accepts a function handle to generate the dialogue window in its Ctor, so that none of the classes really need to be coupled.
If I wanted to go decoupled all the way, I would make the AppMediator class implement some interface and then I would make the apps know that interface rather than the AppMediator implementation so that true decoupling of all the classes can be achieved.
Then, the only one whoes coupled to anything is my main script - startAppMediatorExample which creates the main app (app1) and the mediator and tells the mediator to use app2 as a dialogue.
Hopefully this clarrified the general idea

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